1. Field of the Invention
The present invention relates to a magnetic head parking apparatus of a hard disk drive, and more particularly, to a magnetic head parking apparatus of a hard disk drive separating a magnetic head from a disk in a parking state.
2. Description of the Related Art
A typical hard disk drive, as shown in FIGS. 1A and 1B, includes a hard disk 20 storing predetermined information, and an actuator 30 supporting a slider 50 on which a magnetic head 51 is mounted, and rotating around a rotation shaft 34 provided on a base 10. The actuator 30 includes an arm 32 coupled to the rotation shaft 34 to be capable of pivoting, a suspension 31 installed at the arm 32 and supporting the slider 50 to be elastically biased in a direction in which the slider 50 closely contacts the hard disk 20, and a bobbin portion 33 around which a mobile coil 35 of a voice coil motor, which will be described later, is wound. The voice coil motor includes the mobile coil 35 wound around the bobbin portion 33 and a magnet 41 attached to a yoke 40 installed on the base 10 and generating a magnetic force. Since an electromagnetic force is generated by an interaction between the magnetic force generated by the magnet 41 and a current flowing through the mobile coil 35, the actuator 30 is rotated in a direction according to Flemming's left-hand rule. By controlling the electromagnetic force, the magnetic head 51 is moved to a desired position on the hard disk 20.
During a recording and reproduction work, the slider 50 having the magnetic head 51 mounted thereon receives an elastic force by the suspension 31 and a lift force generated due to a rotation of the hard disk 20. The slider 50 maintains a lifted state at a position where the elastic force and the lift force are balanced, and the magnetic head 51 performs the recording and reproduction work. However, when the hard disk 20 stops rotating, for example, as an electric power is turned off, since the lift force lifting the slider 50 disappears, the slider 50 should be out of a recording area 22 of the hard disk 20 before the magnetic head 51 collides with a surface of the hard disk 20, to prevent the recording area 22 from being damaged. For this purpose, a parking area 21 where the slider 50 is disposed in a parking state is provided at an inner circumference of the hard disk 20. That is, when the actuator 30 is rotated so that the slider 50 is moved over the parking area 21 before the hard disk 20 completely stops rotating, the slider 50 is accommodated in the park area 21 even when the hard disk 20 is stopped, so that the damage to the recording area 22 is prevented. Contrarily, when the hard disk 20 starts to rotate, the lift force is generated again so that the slider 50 is lifted from the parking area 21. The magnetic head 51 is moved to the recording area 22 by rotating the actuator 30. Recently, to facilitate lifting of the slider 50 by reducing a contact area between the slider 50 and the parking area 21 of the hard disk 20, a plurality of bumpers 21a each having a crater shape are formed in the parking area 21 as shown in FIG. 2.
A locking unit 60 is used for locking the actuator 30 so that the actuator 30 disposed in the parking area 21 is not moved. The locking unit 60 includes a magnetic member 62 installed at the yoke 40 and magnetized by the magnet 41, a damper 63 inserted in a coupling protrusion 64 provided at one end of the bobbin portion 33 of the actuator 30, and an iron piece 61 coupled to an end of the damper 63. Thus, when the slider 50 installed at the suspension 31 enters in the parking area 21 of the hard disk 20 as the actuator 30 pivots as shown in FIGS. 1A and 1B, the iron piece 61 is coupled to the magnetic member 62 so that a locking state is maintained.
In the above magnetic head parking mechanism, it is disadvantageous that, when the hard disk 20 restarts to rotate, the slider 50 receives an impact occurring due to a friction with the parking area 21 of the hard disk 20 which rotates until the slider 50 receives the lift force sufficient to be lifted. Furthermore, in a case in which the bumpers 21a are formed, the magnetic head 51 may directly collide with an upward protruding portion of each of the bumpers 21a. 
To solve the above problem, a conventional parking apparatus has been suggested as shown in FIGS. 3 and 4. The conventional parking apparatus includes a ramp 70 installed at an outer circumference of the hard disk 20 so that a tip end portion of the suspension 31 supporting the slider 50 is disposed on the ramp 70 by rotating the actuator 30 when the hard disk 20 is stopped. However, such a mechanism is disadvantageous in that the ramp 70 needs to be designed very precisely so that the tip end portion of the suspension 31 can slide up along a slope surface 71 of the ramp 70. Also, since the suspension 31 repeatedly wbs the ramp 70, an abrasion problem happens. Further, to maintain the tip end portion of the suspension 31 to be disposed on the ramp 70 before the lift force generated by the rotation of the hard disk 20 disappears as shown in FIG. 4, the tip end of the ramp 70 necessarily intrudes into an area of the hard disk 20, e.g., the recording area 22 of the hard disk 20, so that a data space is relatively reduced.
In the meantime, Japanese Patent Publication Nos. Hei 6-60577 and Hei 6-5023 disclose an apparatus for parking a magnetic head installed at one end of a suspension outside a hard disk by elastically deforming a wire to be contracted or expanded by a control of current flowing through the wire so that the magnetic head does not contact a surface of the hard disk. In the apparatus, when the current is supplied to the wire connected to the suspension, the wire contracts and draws the suspension so that a slider is separated from the surface of the hard disk. In this state, an actuator is rotated toward an outside of the hard disk and, when a supply of the current is cut off, the suspension lies on a predetermined support body of the hard disk. In contrast, during an operation of the actuator, the current is supplied to the wire to draw the suspension in a direction to be separated from the surface of the hard disk and the suspension is moved above the hard disk to be lifted by a lift force. However, in the above structure, since the parking apparatus including the wire and a current supply line needs to be mounted on the actuator which transfers the magnetic head, a structure of the actuator is complicated, and a response speed during controlling a rotation of the actuator transferring the magnetic head may become slower. Also, since additional current is supplied to the wire to deform the suspension when the hard disk is operated or the magnetic head is parked, consumption of electrical power increases. Therefore, the parking apparatus is needed to use a new method to overcome the above disadvantages.